And now let's talk about other batteries and chargers, the distinguishing feature of which will be their affordable price. Let's focus on the characteristics of batteries and the minimum necessary functionality of chargers.
I have been using various brands of batteries, including Varta, Duracell, GP, and different Chinese brands, for many years. However, I switched to Eneloop back in 2013, immediately after buying a La Crosse charger to replace my "cool four-channel" Duracell charger that had died. With the help of La Crosse, I saw the mess that my "branded" batteries were after being charged with a Duracell charger – capacity ranging from 600 to 2200mAh and a 30% charge loss within the first few days.
The only batteries that had a capacity that matched their rating and held their charge properly were Sanyo Eneloop and Gsyuasa Enitime, both of which I found were manufactured to the LSD standard after some research. I also found out about HR-3UTGA and HR-3UTGB, which held their charge even better, so I switched to them, thinking that the original is always better than a clone. Gs Yuasa Enitime only started losing capacity at the end of last year (10 years after purchase), while Sanyo batteries still serve me faithfully to this day.
Thus, in 2013, I bought my first smart charger, the La Crosse BC 700, and did my first test cycle. Now, I have a whole laboratory with ten measuring devices. I constantly update my equipment and keep track of new products, so I can not only talk about batteries but also provide figures based on their testing and use in real-world conditions. Testing batteries and chargers has become my second profession, and I have tested hundreds of batteries and dozens of chargers on my test bench. I would like to share my observations with you.
AA and AAA batteries are divided into three categories: "branded," "Chinese," and LSD (low self-discharge). The first two categories can be combined into one under the name "junk." Don't be fooled by fancy names like Duracell or Energizer and numbers like 3000mAh - these are all "instant use" batteries. They discharge very quickly, even without a load (up to 20% in the first day and up to 50% in the first week), can't deliver high current, and die quickly (100 charge-discharge cycles and they're garbage). Worst of all, batteries from the same box may have different characteristics by a factor of two.
LSD batteries have low self-discharge and high current output. They are more expensive and have numbers that are half as large as those on batteries in the first category, but these numbers are honest and they last for more than 1000 charge-discharge cycles. LSD batteries are also great for low-power or rarely used devices (watches, remote controls, flashlights, etc.) - they only lose about 10% of their charge per year. The best batteries in the second category are Eneloop batteries. Interestingly, the top charging devices from SkyRC have a separate program for charging Eneloop batteries. Essentially, it's the same as for charging regular NiMH batteries, but it involves charging at higher currents. Eneloop batteries can easily be charged with a 2A current for an hour, which would make ordinary nickel batteries boil.
They are divided into three categories: "branded", "Chinese" and good ones. The first two categories are combined into one. Most chargers from Duracell, Varta, Energizer, etc. are the same low-quality products as two-dollar chargers from AliExpress, only five times more expensive. Even four-channel chargers can only do one thing, charge. What else do you need? Control!
As I mentioned earlier, the characteristics of bad batteries can differ by a factor of two right out of the box. But even with good batteries (remember, these are LSD batteries), the characteristics begin to fluctuate after some use. Imagine that you put four batteries in a flash that you only know one thing about: they are fully charged. But here's the problem: three batteries have a nominal capacity, and the fourth one you accidentally dropped and its capacity has been reduced by half. You put them in the flash, and it stops working after 20 shots. You think the batteries are dead and throw away the entire set, although you could have bought one more battery and used the set for many more years.
So, good chargers can show how discharged each battery is, how much was put into each during charging, calculate the capacity of each battery, and the best ones can even restore it. The best affordable chargers for AA and AAA batteries today are the SKYRC NC1500, and the best universal charger is the Opus BT-C3100 V2.2.
"Popular" Liitokala Lii-500S, Lii-600, and others - are a matter of taste. Clicking on the name will open reviews of these devices, from which you will understand why I do not recommend them.
There are more universal chargers available. For example, SkyRC B6 Nano. Its advantage is the ability to charge anything and everything, from radio-controlled model batteries to lead-acid car and lithium camera and cell phone batteries. The downside is that excessive universality greatly complicates the device, and in general, for full use, a basic understanding of the basics of electrical engineering is required, and you need to buy additional wires with connectors and sockets for each battery size.
The SKYRC MC3000 is currently the king of battery chargers for all (absolutely all) types and sizes of batteries. It can charge NiCd, Ni-MH, Li-ion, LiFePO4, NiZn batteries in sizes C, D, AA, AAA, 18650, 14500, 16340, 32650, 14650, 17670, 10440, 18700, 18350, RCR123, AAAA, 18500, 18490, 25500, 13500, 13450, 16650, 22650, 17500, 10340, 17650, 10500, 26500, 12340, 12500, 12650, 14350, 14430, 16500, 17350, 20700, 21700, 22500, 32600, and Sub-C. In addition, the MC3000 has a Bluetooth interface and can display the battery status directly on your smartphone. Although it is relatively expensive and not very popular, this device guarantees the most comfortable charging conditions and, consequently, maximum service life for your batteries.
And finally, a piece of advice. The main rule when switching to good batteries is to choose one specific brand and buy several sets of them at once, because using batteries from different manufacturers (even with the same capacity) is inefficient due to different discharge characteristics.
For example, they all give 2000mAh when discharged from maximum to 0.9V (this is considered a full discharge), but some batteries discharge faster in the range of 1.2-1.1V, while others in the range of 1.1-1.0V. Or they may heat up differently under load. When installing them in one set, due to different discharge curves, a situation may arise where one battery discharges to zero and the other elements begin to charge it in the opposite direction, which will lead to the battery being damaged. Today you have four batteries with 2000mAh each, and tomorrow only three.
The article is already 8 years old, but I constantly update it, so the above remains true for 2023 as well. In 2015, I purchased a charging device that I still use (here is a review and testing of Opus BT-C3100). In version 2.2, it is completely rid of its childhood diseases and remains the optimal purchase to this day. Sometimes it is available for sale under the brand name Zeepin with the same labeling. The big advantage of the Opus 3100, besides the ability to charge lithium and nickel batteries simultaneously (a switch for 4.2V/4.35V/3.7V is provided for charging LiHV and LiFePo4), is its forced cooling during charging, which reduces the likelihood of overheating the cells (and it can charge them with currents up to 2 amps, which implies significant heating). The second advantage is the ability to use it in a car with direct power from the cigarette lighter socket (12 volts). Well, everything else is also at the level - conditioning, internal resistance measurement, constant current charging for lithium and -ΔV for nickel batteries.